1. Field of the Invention
The present invention relates to a method for modifying wettability of a surface of an inorganic material. More specifically, the invention relates to a method for modifying wettability of a surface of an inorganic material by an X-ray irradiation to the surface of the inorganic material.
2. Background of the Related Art
Controlling and modifying the wettability on solid surface are important in many industrial applications. In particular the dynamic tuning of the wettability to superhydrophobicity (contact angle (CA)>150°) or superhydrophilicity (CA<10°) by external stimuli is a subject of keen interest because of its potential applications to many intelligent devices such as biosensors, microfluidic devices, and intelligent membranes.
Various external stimuli such as pH, light irradiation, electric field, and temperature have been reported for dynamic tuning of wettability. Among them, light irradiation as remote stimulus is especially attractive because of individually addressable switching, remote controllability, and easy selectivity of wavelength.
Owing to their good chemical and mechanical stabilities, inorganic materials can be applied, if their wettability triggered by UV/visible irradiation, to a variety of applications such as Si-based μ-TAS (micro-total-analytical system), Al2O3-modified microcantilevers (MCLs), and smart windows. However smooth surfaces of inorganic materials except for ZnO, TiO2, and WO3 usually show limited variation of wettability by UV/visible irradiation. Nanostructures with rough surfaces are, therefore, introduced to enhance the wettability variation.
However the fabrication of nanostructures is often accompanied by complex processes and shows poor reproducibility. Furthermore it is not easy to fabricate nanostructures on complex structures. A challenging demand is, therefore, to find a new light irradiation that enables to universally improve the wettability variation on smooth surfaces of inorganic materials.